AI agents invoke simple_highs_solver to trigger actions in USolver. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
Based on the server context, this tool likely executes the HiGHS numerical/LP solver to process optimization problems. Execution of a solver is an Execute-category action. The empty description prevents higher confidence, but the naming pattern and server description strongly imply solver execution with no destructive or financial side effects.
From the tool's definition Tool name 'simple_highs_solver' suggests it runs the HiGHS optimization solver; description is empty and uninformative, lowering confidence. Sibling tools like 'solve_highs_problem' confirm this server executes dedicated solvers (ortools, cvxpy, z3, HiGHS).
Documented attack patterns abuse exactly the kind of access simple_highs_solver gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and USolver, and nothing reaches the server without passing your rules. This is the rule we recommend for simple_highs_solver:
{
"version": "1",
"default": "deny",
"tools": {
"simple_highs_solver": {
"limits": [
{
"counter": "simple_highs_solver_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}simple_highs_solver stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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simple_highs_solver. It is categorised as a Execute tool in the USolver MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the USolver MCP server in PolicyLayer and add a rule for simple_highs_solver: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches USolver. Nothing to install.
simple_highs_solver is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the simple_highs_solver rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for simple_highs_solver. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
simple_highs_solver is provided by the USolver MCP server (sdiehl/usolver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 USolver tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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10 USolver tools catalogued and risk-classified — across an index of 42,500+ MCP servers.